Double-disk refiner



May 2, 1961 D. w. CURTIS DOUBLE-DISK REFINER Filed June 1, 1960INVENTOR. )arzald W flarl United sta e Paten "10 DOUBLE-DISK REFINERDonald w. Curtis Pittsfield, Mass., assignor to E. D. Jones Corporation,Pittsfield, Mass, a corporation of Delaware Filed June 1, 1960, Ser. No.33,238

4 Claims. (Cl. 241-33) This invention relates to machines for refiningpaper pulp and other materials but more particularly to machines of theso-called double-disk type comprising a rotary disk having a set ofblades on each side and a set of stationary blades facing each of saidsets with a passageway extending radially between the blades of eachpair of opposed rotary and stationary blades and a circumferential spaceinterconnecting the outer ends of said passageways, with an inlet to theinner end of one of the passageways and an outlet from the inner end ofthe other passageway. Such a machine is disclosed in Patent No.2,690,098, granted September 24, 1954, to Dwight E. Jones et a1.

One difficulty with machines of this kind is that variations in the rateof fiow of materials through a machine produce unequal pressures onopposite sides of the rotating disk thereby crowding the rotating diskcloser to one or the other stationary disks. This makes one passagewaynarrower than the other so that the refining actions in the twopassageways are not the same and so that excessive wear occurs on theblades in the passageway which is narrower.

Objects of the present invention are to provide apparatus which issimple and economical in construction and which automatically equalizesthe pressure on opposite sides of the rotating disks and equalizes wearon the two sets of blades.

According to the present invention the apparatus is characterized by aby-pass leading from said circumferential space to said inlet, with ,athrottle valve in the by-pass, whereby the pressure drop between theinlet and the outlet may be controlled by varying the opening in thethrottle valve. By maintaining this pressure drop constant the widths ofthe aforesaid passageways will remain equal after being adjusted tothatparticular pressure drop. Preferably the throttle valve iscontrolled automatically by a diflerential pressure device connectedbetween the inlet and the outlet. Such devices are made and sold by theFoxboro Company, of Foxboro, Massachusetts, and are described in theirPatents 2,539,892; 2,761,471; 2,770,- 258; and 2,806,480.

For the purpose of illustration a typical embodiment of the invention isshown in the accompanying drawing in which the parts are constructed andarranged as in the aforesaid patent of Dwight E. Jones et al.

The apparatus comprises a rotating'disk 1, having blades 2 and 3 onopposite side and two sets of stationary blades 4 and 5 opposed to therotary blades with passageways 6 and 7 between the pairs of opposedrotary and stationary blades respectively. Extending around the disk isa circumferential space 8 interconnecting the two passageways. Materialis fed to the inner end of passageway 6 through an inlet 9 and thematerial is delivered from the inner end of the passageway 7 through anoutlet 10.

According to this invention a by-pass 11 extends from the space 8 to theinlet 9 and in the by-pass is a throttle valve 12 for regulating theamount of material lay-passed from the space to the'inlet 9. Theaforesaid difieren valve through a'connection 16 which may be pneumatic,

' hydraulic or electrical as is well known.

In use the disks are adjusted as described in the aforesaid patent ofDwight E. Jones, et al., so that the passageways 6 and 7 are equal inwidth for the rate of fiow to be maintained in a particular run ofmaterial. Then the pressure differential device is adjusted to maintaina predetermined pressure drop between the inlet and outlet, this beingestablished by controlling the amount of recirculation thru the by-pass.If the difierential pressure between the inlet and outlet tends to riseabove the predetermined value the throttle valve tends to close and ifthe difierential pressure tends to drop below the predetermined valuethe throttle valve tends to open. In this way the pressure drop betweeninlet and outlet is kept constant and the pressures on opposite sides ofthe rotating disk 1 remain equal.

It should be understood that the present disclosure is for the purposeof illustration only and that this invention includes all modificationsand equivalents which fall within the scope of the appended claims.

I claim:

1. Refining apparatus comprising a rotary' disk having a set of bladeson each side, a set of stationary blades facing each of said sets with aradial passageway extending between the blades of each pair of opposedrotary and stationary blades and a circumferential space interconnectingthe outer ends of said passageways, an inlet to the inner end of one ofsaid passageways and an outlet from the inner end of the otherpassageway, characterized by a by-pass leading from said space to saidinlet, and a throttle valve in said by-pass, whereby the pressure dropbetween the inlet and outlet may. be controlled by varying the openingin the throttle valve.

2. Refining apparatus comprising a rotary disk having a set of blades oneach side, a set of stationary blades facing each of said sets with aradial passageway extending between the blades of each pair of opposedrotary and stationary blades and a circumferential space interconnectingthe outer ends of said passageways, an inlet to the inner end of one ofsaid passageways and an outlet from the inner end of the otherpassageway, characterized by a by-pass leading from said space to saidinlet, an automatic throttle valve in said by-pass, and a differentialpressure device hydraulically connected between said inlet and outletfor controlling said throttle valve.

3. Refining apparatus comprising a rotary disk having a set of blades oneach side, a set of stationary blades facing each of said sets with apassageway extending radially between the blades of each pair of opposedrotary between said inlet and outlet, a by-pass from said space to saidinlet, and a controller in said by-pass responsive to said device forcontrolling the amount of recirculation through the by-pass.

4. Refining apparatus comprising a rotary diskhaving a set of blades oneach side, a set of stationary blades facing each of said sets with apassageway extending radially between the blades of each pair of opposedrotary and stationary blades throughout the circumference of the ar 961f3 disk, a housing having a space around said disk and an inlet leadingto theinner end of one of said passageways and an outlet leading fromthe inner end of the other of said passageways so that material may flowoutwardly through one passageway to said space and thence inwardlythrough the other passageway to said outlet, a differential-pressuredevice hydraulically interconnected between said inlet and outlet, aby-pass from said space to said inlet, and an automatic throttle yalvein said bypass responsive to said device for controlling the amountUNITED STATES PATENTS Fraser Mar. 16, 1954 Jones et al. Sept. 26, 1954Jones et al. Dec. 20, 1955 Bowditch Sept. 17, 1957

